Susanne Fischer

This atlas provides updated maps based on georeferenced tick locations of 22 species endemic in Germany, three regularly imported tick species and one species that was previously frequently imported into Germany. Thus, the current version of the atlas of ticks in Germany contains distribution maps for a total of 26 tick species with the following numbers of newly georeferenced tick locations: 1 Argas reflexus , 10 Carios vespertilionis , 3 Dermacentor marginatus , 53 Dermacentor reticulatus , 10 Haemaphysalis concinna , 7 Haemaphysalis punctata , 2 Hyalomma aegyptium , 111 Hyalomma marginatum , 39 Hyalomma rufipes , 2 Ixodes arboricola , 2 Ixodes crenulatus (syn. Ixodes canisuga ), 27 Ixodes frontalis , 43 Ixodes hexagonus , 6 Ixodes lividus , 271 Ixodes ricinus , 1 Ixodes rugicollis , 5 Ixodes trianguliceps , 1 Ixodes uriae , 2 Ixodes ventalloi , 1 Ornithodoros maritimus , and 32 Rhipicephalus sanguineus sensu lato. Ixodes inopinatus has been removed from the previously included species list because more recent studies have shown that these were misidentifications. The rabbit tick I. ventalloi , the argasid seabird tick O. maritimus and the formerly frequently imported tortoise tick Hy. aegyptium , however, have been included in the current atlas of ticks in Germany. In total, the digital dataset available for Germany is updated by 629 new tick locations. These records increase the number of tick species mapped in the federal state Saxony by six, those in Hamburg by five, those in Brandenburg by four, those in Schleswig-Holstein by three, those in Baden-Wuerttemberg, Bavaria and Thuringia by two each, and those in Bremen, Northrhine-Westphalia, Rhineland Palatinate and Saarland by one each. Of the 26 tick species ever detected in Germany, 21 were observed in the period 2001–present. Thus, the second data update of the atlas of ticks in Germany provides the most comprehensive digital dataset to date on the distribution of tick species in Germany.

Background: Ticks are important ectoparasites for both humans and animals and can also transmit a wide range of different viral, bacterial, and parasitic pathogens, which are commonly known as “tick-borne pathogens” (TBPs). In Zambia (Southern Africa), a number of studies have been conducted on TBPs, but information on their distribution and genetic variation is still incomplete. Methods: Between 2022 and 2023, 588 ticks were collected in 3 provinces from the environment/vegetation via flagging as well as from cattle and wild host species (buffaloes and tortoises). After tick species identification and DNA/RNA extraction, the samples were tested for viral (orthonairo-, flavi- and arenaviruses) and bacterial ( Rickettsia , Anaplasma , Ehrlichia , and Coxiella ) pathogens using different polymerase chain reaction (PCR) assays. Subsequently, positive samples were sequenced and analyzed on the basis of different genes ( rrs (16S rRNA); 23S-5S intergenic spacer region; ompB ; gltA ; sca4 ). Results: Apart from some Hyalomma and Amblyomma species, most of the ticks collected belonged to the genus Rhipicephalus, in which Rhipicephalus appendiculatus made up the largest proportions. No viral RNA was detected inside the ticks, but Rickettsia ( Ri. africae , Ri. aeschlimannii , Ri. sibirica, Ri. tamurae -like agent), Anaplasma ( An. bovis , An. marginale , An. platys, An. phagocytophilum -like agent), and Ehrlichia species ( Eh. ruminantium , Eh. chaffeensis -like agent) were most frequently found. Conclusions: Many of the pathogens found had already been described in Zambia. Nevertheless, there were some unexpected findings. The detection of Ri. sibirica ( ompB and 23S-5S spacer region; in ticks from cattle) or Eh. chaffeensis -like amplicons ( rrs ; in a questing Rh. appendiculatus tick) may suggest that some pathogens or closely related species might be more widespread than previously assumed. In addition to these rarely described pathogens in Africa, further studies should be carried out on the detection of TBPs of viral origin. Graphical

Background: The zoonotic intracellular alpha-proteobacterium Anaplasma phagocytophilum is a tick-transmitted pathogen. The associations between vertebrate reservoirs and vectors are described as wide-ranging, and it was previously shown that the pathogenicity of A. phagocytophilum differs depending on the combination of pathogen variant and infected host species. This leads to the question of whether there are variations in particular gene loci associated with different virulence. Therefore, this study aims at clarifying existing host-variant combinations and detecting possible reservoir hosts. To understand these interactions, a complex toolset for molecular epidemiology, phylogeny and network theory was applied. Methods: Sequences of up to four gene loci (msp4, msp2, groEL and 16S rRNA) were evaluated for different isolates from variable host species, including, for example, dogs, cattle and deer. Variant typing was conducted for each gene locus individually, and combinations of different gene loci were analysed to gain more detailed information about the genetic plasticity of A. phagocytophilum. Results were displayed as minimum spanning nets and correlation nets. Results: The highest diversity of variants for all gene loci was observed in roe deer. In cattle, a reduced number of variants for 16S rRNA [only 16S-20(W) and 16S-22(Y)] but multiple variants of msp4 and groEL were found. For dogs, two msp4 variants [m4-20 and m4-2(B/C)] were found to be linked to different variants of the other three gene loci, creating two main combinations of gene loci variants. Cattle are placed centrally in the minimum spanning net analyses, indicating a crucial role in the transmission cycles by possibly bridging the vector-wildlife cycle to infections of humans and domestic animals. The minimum spanning nets confirmed previously described epidemiological cycles of the bacterium in Europe, showing separation of variants originating from wildlife animals only and a set of variants shared by wild and domestic animals. Conclusions: In this comprehensive study of 1280 sequences, we found a high number of gene variants only occurring in specific hosts. Additionally, different hosts show unique but also shared variant combinations. The use of our four gene loci expand the knowledge of host–pathogen interactions and may be a starting point to predict future spread and infection risks of A. phagocytophilum in Europe. Graphical

Anaplasma phagocytophilum is an obligate intracellular bacterium that causes granulocytic anaplasmosis in domestic animals, wildlife, and humans and is primarily transmitted by ticks of the Ixodes persulcatus complex. This retrospective study aims to determine the percentages of dogs that tested positive for A. phagocytophilum in Germany. It included the results of direct (polymerase chain reaction [PCR]) and indirect (immunofluorescence antibody test [IFAT], antibody-enzyme-linked immunosorbent assay [ELISA]) detection methods performed in the laboratory LABOKLIN on canine samples provided by German veterinarians from 2008 to 2020. Out of a total of 27,368 dogs tested by PCR, 1332 (4.9%) tested positive, while 24,720 (27.4%) of the 90,376 dogs tested by IFAT/ELISA had positive serology. High rates of positive PCR results were observed in months with known peaks in vector activity, showing that the dynamics of A. phagocytophilum infections in dogs in Germany are consistent with vector activity. In dogs with a positive PCR result, peaks in serology could be observed four weeks after initial testing. Male and senior dogs had higher rates of positive serology. A possible impact of environmental factors such as changes in climate should be investigated further. Overall, the upward trend in positive test results over the years indicates that canine granulocytic anaplasmosis will continue to become increasingly important for veterinary medicine.

Knowledge on the occurrence of pathogenic tick-borne bacteria Anaplasma phagocytophilum and Anaplasma ovis is scarce in sheep from Germany. In 2020, owners from five flocks reported ill thrift lambs and ewes with tick infestation. Out of 67 affected sheep, 55 animals were clinically examined and hematological values, blood chemistry and fecal examinations were performed to investigate the underlying disease causes. Serological tests (cELISA, IFAT) and qPCR were applied to all affected sheep to rule out A. phagocytophilum and A. ovis as a differential diagnosis. Ticks were collected from selected pastures and tested by qPCR. Most animals (n = 43) suffered from selenium deficiency and endoparasites were detected in each flock. Anaplasma spp. antibodies were determined in 59% of examined sheep. Seventeen animals tested positive for A. phagocytophilum by qPCR from all flocks and A. phagocytophilum was also detected in eight pools of Ixodes ricinus. Anaplasma phagocytophilum isolates from sheep and ticks were genotyped using three genes (16S rRNA, msp4 and groEL). Anaplasma ovis DNA was identified in six animals from one flock. Clinical, hematological and biochemical changes were not significantly associated with Anaplasma spp. infection. The 16S rRNA analysis revealed known variants of A. phagocytophilum, whereas the msp4 and groEL showed new genotypes. Further investigations are necessary to evaluate the dissemination and health impact of both pathogens in the German sheep population particularly in case of comorbidities.

Babesiosis caused by the Babesia species is a parasitic tick-borne disease. It threatens many mammalian species and is transmitted through infected ixodid ticks. To date, the global occurrence and distribution are poorly understood in questing ticks. Therefore, we performed a meta-analysis to estimate the distribution of the pathogen. A deep search for four electronic databases of the published literature investigating the prevalence of Babesia spp. in questing ticks was undertaken and obtained data analyzed. Our results indicate that in 104 eligible studies dating from 1985 to 2020, altogether 137,364 ticks were screened with 3069 positives with an estimated global pooled prevalence estimates (PPE) of 2.10%. In total, 19 different Babesia species of both human and veterinary importance were detected in 23 tick species, with Babesia microti and Ixodesricinus being the most widely reported Babesia and tick species, respectively. Regardless of species, adult ticks with 2.60% had the highest infection rates, while larvae had the least with 0.60%. Similarly, female ticks with 4.90% were infected compared to males with 3.80%. Nested-polymerase chain reaction (PCR) 2.80% had the highest prevalence among the molecular techniques employed. In conclusion, results obtained indicate that Babesia species are present in diverse questing tick species at a low prevalence, of which some are competent vectors.

Viral disease outbreaks remain a significant limiting factor for aquaculture. The majority of licensed vaccines used in the industry are administered as oil-adjuvanted formulations carrying inactivated whole pathogens. Cell-mediated immune responses, in particular those based on virus-specific cytotoxic T-cells (CTLs) to conventional inactivated oil-based vaccines, are largely unexplored. As vaccines cannot be optimized against viral pathogens if knowledge of host cellular immune mechanisms remains unknown, in this study we examined fundamental cell-mediated immune responses after vaccination of rainbow trout with an oil-adjuvanted inactivated vaccine against salmonid alphavirus (SAV) and after infection with SAV. A unique in vitro model system was developed to examine MHC class I restricted CTL responses in a clonal line of rainbow trout. The levels of cell-mediated cytotoxicity were compared to pathology, virus load, specific antibody response, changes in immune cell populations, and mRNA expression. Our results hint that different protective mechanisms are being triggered by infection compared to vaccination. While vaccination itself did not cause a strong cytotoxic or humoral response, subsequent challenge of vaccinated fish resulted in significantly stronger and faster specific cytotoxicity, alongside reduced viral titers and pathology. Hence, testing a vaccine on the capacity to induce cell-mediated cytotoxicity will still require a challenge test. Examination of cellular markers additionally indicates that the initial innate response induced by the vaccine could play an important role in steering adaptive mechanisms.

Background: Anaplasma marginaleis an obligate intracellular bacterium and the main cause of bovine anaplasmosis in tropical and subtropical regions. In Egypt, data regarding the prevalence ofA. marginalein ruminant hosts and of the circulating genotypes is lacking. This study therefore aimed to (i) investigate the presence, epidemiology and genotypes ofA. marginalein cattle and buffaloes in Egypt, (ii) to evaluate suitable diagnostic tools and (iii) to identify co-infections ofA. marginalewith other selected tick-borne pathogens.Methods: Blood samples were collected from 394 animals (309 cattle and 85 buffaloes) from three different areas in Egypt. For the detection ofA. marginaleinfection, several tests were compared for their sensitivity and specificity: blood smear analysis, enzyme-linked immunosorbent assay (ELISA), PCR, real-time PCR and reverse line blot (RLB) assay. Co-infections withA. marginale,piroplasms and otherAnaplasmataceaewere surveyed by RLB whileA. marginalegenotypes were identified by amplifying and sequencing the partialmsp1αgene.Results: Anaplasma marginaleDNA was amplified by qPCR in 68.3% of cattle and 29.4% of buffaloes. RLB showed infection withA. marginalein 50.2% of cattle and 42.5% of buffaloes. Blood smear analysis detected this agent in 16.2% of cattle and 2.4% of buffaloes. ELISA showed specific antibodies againstA. marginalein 54.9% of cattle.Anaplasma marginalewas associated, in cattle and buffaloes, with several tick-borne pathogens (Theileria annulata,Babesia bovis,Babesia bigemina,Babesia occultansandAnaplasma platys). A significant difference ofA. marginaleinfection level was noticed in cattle, where animals between 3–5-years-old had a higher prevalence (79.2%) compared to those older than 5 years (36.4%) and younger than 3 years (59.7%) and one year (64.5%), respectively (P = 0.002281). Microsatellite analysis identified 15 different genotypes.Conclusions: The epidemiological findings revealed high prevalence ofA. marginalein cattle and buffaloes in all the investigated areas. The circulation of diverse genotypes was observed, most of theseA. marginalegenotypes being specific for Egypt. The qPCR assay was confirmed to be the most sensitive tool for detection ofA. marginalein cattle and buffaloes even in the carrier state, highlighting the importance of using suitable diagnostic tests.

Background: Ticks are hematophagous arthropods responsible for maintenance and transmission of several pathogens of veterinary and medical importance. Current knowledge on species diversity and pathogens transmitted by ticks infesting camels in Nigeria is limited. Therefore, the aim of this study was to unravel the status of ticks and tick-borne pathogens of camels in Nigeria. Methods: Blood samples (n = 176) and adult ticks (n = 593) were collected from one-humped camels (Camelus dromedarius) of both sexes in three locations (Kano, Jigawa and Sokoto states) in north-western Nigeria and screened for the presence of Rickettsia spp., Babesia spp., Anaplasma marginale, Anaplasma spp. and Coxiella-like organisms using molecular techniques. All ticks were identified to species level using a combination of morphological and molecular methods. Results: Ticks comprised the three genera Hyalomma, Amblyomma and Rhipicephalus. Hyalomma dromedarii was the most frequently detected tick species (n = 465; 78.4%) while Amblyomma variegatum (n = 1; 0.2%) and Rhipicephalus evertsi evertsi (n = 1; 0.2%) were less frequent. Other tick species included H. truncatum (n = 87; 14.7%), H. rufipes (n = 19; 3.2%), H. impeltatum (n = 18; 3.0%) and H. impressum (n = 2; 0.3%). The minimum infection rates of tick-borne pathogens in 231 tick pools included Rickettsia aeschlimannii (n = 51; 8.6%); Babesia species, (n = 4; 0.7%) comprising of B. occultans (n = 2), B. caballi (n = 1) and Babesia sp. (n = 1); Coxiella burnetii (n = 17; 2.9%); and endosymbionts in ticks (n = 62; 10.5%). We detected DNA of “Candidatus Anaplasma camelli” in 40.3% of the blood samples of camels. Other tick-borne pathogens including Anaplasma marginale were not detected. Analysis of risk factors associated with both tick infestation and infection with Anaplasma spp. in the blood indicated that age and body condition scores of the camels were significant (P < 0.05) risk factors while gender was not. Conclusions: This study reports low to moderate prevalence rates of selected tick-borne pathogens associated with camels and their ticks in north-western Nigeria. The presence of zoonotic R. aeschlimannii emphasizes the need for a concerted tick control programme in Nigeria.